Preparation And Property Of Co-Cu-Mn-Fe Nanocrystalline Black Ceramic Pigments Via Solution Combustion Technique

The main components of black ceramic pigments prepared are the fourth period of transition metal oxide compounds. The tinting strength of pigments is related to the molar ratio of transition metal ion, the particles size, and the size distribution as well. The preparation of black pigments with small particle size, narrow size distribution and high tinting strength has become a recent challenge. In this dissertation, Co-Cu-Mn-Fe system nanocrystalline black pigments were synthesized by a solution combustion method with iron nitrate, cobalt nitrate, manganese nitrate, copper nitrate and DL-alanine as raw materials. In addition, the physical and chemical properties of the pigments were also investigated.Firstly, Co-Cu-Mn-Fe black pigments were obtained under the optimimum condition. The effects of the ignition temperature and the amount of fuel in the reaction were also investigated. The results show that the nanocrystalline black pigments with the average crystalline size of 16.4 nm and the average particle size of 1 μm are obtained at the stoichiometric ratio of organic fuel to oxidizer(according to the principle of propellant chemistry) and the ignition temperature of 400 ℃ and Co2+:Cu2+:Mn2+:Fe3+ of 0.5:0.5:1:1. The values of L*, a*, b* are 39.95, 0.25 and 0.16, respectively. The effective synthesis can occur at a higher ignition temperatue, but the synthesized product becomes poor dispersive. The sample obtained from the stoichiometric fuel system has better dispersion and smaller particles size than other samples obtained from fuel-lean system and fuel-rich system.Secondly, the effects of the type/amount of inert salt and the ammonium nitrate on the reaction process and the product properties were investigated. The results show that the average particles sizes of the product without salt and with lithium chloride, sodium chloride and potassium chloride are 1 μm, 650 nm, 400 nm and 300 nm, respectively. The corresponding specific surface areas are 19.75 m2/g, 32.46 m2/g, 142.50 m2/g and 131.66 m2/g, respectively. The particles size and the specific surface area of the products are related to the solubility of the inert salt. The higher solubility of inert salt, the greater particle and the smaller specific surface area will be. A certain amount of inert salt in the reaction can give the smaller crystallines/particles. The excessive inert salt can cause the unsufficient reaction, thus leading to the ineffective preparation of the target product. The product with the greater crystallines/particles and the serious agglomeration is obtained when ammonium nitrate is added.Thirdly, the tinting performances of Co-Cu-Mn-Fe system nanocrystalline pigments in glazes(i.e., zinc glaze, magnesium glaze, barium-containing transparent glaze, barium-containing matte glaze and high boron glaze) were investigated. The results show that the tinting performances of pigments in zinc glaze and magnesium glaze are unstable, while those in barium glaze and boron glaze are better. The tinting performance in high boron glaze is superior. It is indicated that the pigment can be used in barium glaze and boron glaze rather than in zinc glaze and magnesium glaze.Finally, this dissertation gives the conclusions and some prospects for future work based on the experimental results obtained.